With regard to, for example, cupboard sides, screening systems and similar, included units normally comprise of one element only, having respectively side planes and edge surfaces arranged with a protective and/or decorative surface coating. When applying a surface against both sides of the board-shaped elements there is an obvious risk for surface damage, during manufacture as well as during distribution. The board-shaped elements often comprise of a homogeneous material, and when delivered in a disassembled fashion, the products often include many visible coupling fittings. When for example two cupboard units are mounted side by side, decorative surfaces in contact with each other are obviously without any value. Furthermore, any electrical wiring in such units will obviously be visible.
EP-A1-0 316 242 discloses a board-shaped unit, comprising of two board-shaped elements located adjacent to each other, internally joined by means of a surrounding coupling list engaging with the board-shaped elements. A surrounding groove is arranged in one of the board-shaped elements, engaging with a protruding member from the coupling list. The outer side portion of the other board-shaped element is seized by a member protruding from the coupling list, and between the board-shaped elements are elastically deformable separating elements arranged, which cause a separating force which results in that the surrounding coupling list is maintained in position. A further previously known solution utilizing an embracing coupling list is disclosed in DE-A-2 216 248, and includes a coupling list having a substantially U-shaped section, having the outer open portion arranged with the legs separated with a larger distance than at the bottom portion of the section. A stop is thus formed by each leg in conjunction with the change between a larger and a smaller leg separation, whereagainst a board-shaped element, having a width substantially corresponding to the internal width at the outer portion of the section, can be inserted into an abutting position. A screw connection, extending through the section in the area between the stop surfaces and the bottom portion of the section, is used to hold a board-shaped element inserted into the outer portion of the section by means of a squeezing action. GB-A-2 060 118 discloses a device to join profiles demountably by means of an excentric action joining means. A section having T-shaped grooves is used, whereagainst hollow sections having square or rectangular cross-section can be connected by means of a joining means, which extends out from the end portion of a hollow section with a member arranged to engage with a T-shaped groove. A member having excentric action co-acting with the joining means, and being located surrounded by the hollow section, is accessible through a hole taken up by one side of the section, and can be rotated by manual influence, thereby moving the joining means further into the hollow section, thereby pressing same against the section including the aforementioned T-groove.